Teilautomatisiertes preforming zur Qualitätssicherung und Verkürzung von Fertigungszeiten bei der Herstellung von Rotorblättern von Windenergieanlagen

Quality management and reduction of processing time through automised preforming in the rotorblade manufacturing for wind turbines Rotor blades of wind turbines are mainly manufactured from fibre reinforced plastics. These materials show an excellent performance concering the ratio of stiffness and weight. Basically the composite material of rotor blades is made out of glass fibres and thermosetting material. But growing technological and economical requirements to rotor blades by off‐shore‐application, in particular through increasing rotor blade diameter, have to meet successful. Although reduction of processing time and increased quality of rotor blades play a major role. To achieve the increasing requirements of the rotor blade manufacturing the Bremen Institute for Engineering Design and the rotor blade manufacturer Abeking & Rasmussen Rotec GmbH are working together on the handling and manufacturing of textile preforms. Preforms are made out of stacked and bonded dry textile layers and deposited in the mould as one textile part. Preforming allows the parallel processing of some manufacturing steps. This shows great advantages in the production of fibre reinforced plastics because of the long curing time of the resin component. This parallel processing is required to reach the aim of decreased overall cycle time. This essay is focussing on the handling of textiles and the textile preforming. Summarised aspects of quality management and economics in textile preforming will be discussed with the aim of automising the preforming process.     

Simultaneous binding and ex situ toughening concept for textile reinforced pCBT composites: Influence of preforming binders on interlaminar fracture properties

A new concept consisting of binding and ex situ toughening is proposed for manufacturing and toughening of textile reinforced pCBT composites. The present study assesses the influence of various preforming binders on interlaminar fracture properties. Interlaminar fracture toughness of textile reinforced pCBT composites was investigated under mode I and mode II deformation. A standard double cantilever beam (DCB) test and an end notched flexure (ENF) test based on a three-point bending test were applied to evaluate the interlaminar fracture toughness in mode I and mode II, respectively. The effect of binder type, filling content and preparation concept on fracture properties under the mentioned two deformation modes were discussed on the basis of morphology analysis of fracture sections with scanning electric microscopy. Flexural properties of the textile reinforced pCBT laminates prepared using the selected preforming binder were characterized for further verification of the performance of the proposed concept.     

钢格板计算机辅助设计与优化排料系统研究与开发

钢格栅板广泛应用于建筑、化工、水利等领域。钢格板设计与生产流程普遍存在的诸多问题影响了企业的生产效率。系统通过集成自动布板、工作量统计与优化排料等功能对钢格板设计、生产流程进行全程优化,显著提高了钢格板的设计生产效率。结合某应用实例验证本系统的实用性和可靠性。     

Applying Job Shop Scheduling to SMEs Manufacturing Platform to Revitalize B2B Relationship

A small and medium enterprises (SMEs) manufacturing platform aims to perform as a significant revenue to SMEs and vendors by providing scheduling and monitoring capabilities. The optimal job shop scheduling is generated by utilizing the scheduling system of the platform, and a minimum production time, i.e., makespan decides whether the scheduling is optimal or not. This scheduling result allows manufacturers to achieve high productivity, energy savings, and customer satisfaction. Manufacturing in Industry 4.0 requires dynamic, uncertain, complex production environments, and customer-centered services. This paper proposes a novel method for solving the difficulties of the SMEs manufacturing by applying and implementing the job shop scheduling system on a SMEs manufacturing platform. The primary purpose of the SMEs manufacturing platform is to improve the B2B relationship between manufacturing companies and vendors. The platform also serves qualified and satisfactory production opportunities for buyers and producers by meeting two key factors: early delivery date and fulfillment of processing as many orders as possible. The genetic algorithm (GA)-based scheduling method results indicated that the proposed platform enables SME manufacturers to obtain optimized schedules by solving the job shop scheduling problem (JSSP) by comparing with the real-world data from a textile weaving factory in South Korea. The proposed platform will provide producers with an optimal production schedule, introduce new producers to buyers, and eventually foster relationships and mutual economic interests.     

物流业与制造业集群的协同发展问题研究

通过绍兴轻纺业集群的案例,在数据分析的基础上探讨了物流服务业和制造业集群之间的协同发展关系,证明了协同发展能够提升其二者各自的生产效率及利润,从而提升整个区域经济的总体竞争力.     

Challenges for composites into the next millennium — a reinforcement perspective

This paper summarises the current level of technology within the manufacturing processes of filament winding, fibre placement, pultrusion and advanced textile preforming. It also examines the current problems within each of these manufacturing techniques and the areas of predicted future development.     

Space technology moves textiles‘smart’

The European Space Agency's Technology Transfer Network which met with 72 representatives of 53 European and Canadian textile companies in Lille, France had as focus a workshop brainstorming how technology developed for space could improve textiles, fibre products, clothes and textile manufacturing equipment. Lille is situated in one of Europe's centres of textile production. More than 1100 French textile industries are based in the area and a similar sized market lies just across the border in Belgium. The workshop was organised by ESA's Technology Transfer and Promotion office (TTP) together with its network of technology brokers represented by MST Aerospace, D'Appolonia, JRA and Nodal and Lille's Chamber of Commerce.     

Aspects of the stitch formation process on the quality of sewn multi-textile-preforms

Stitching technologies are considered to be one of the key technologies for automated manufacturing of complex textile preforms which are used for liquid composite moulding of fibre reinforced plastic parts [Proceedings of Sixth International Conference on Automated Composites (1999)]. The sewing or stitching process is applied for different purposes during the production of dry fibrous reinforcements as well as for structural aims in the composite component (through-the-thickness reinforcement), thus, the requirements on the stitch itself are wide spread [Complex Multi-textile Preforms – The Potential of Sewing. 90(4) (2000) 43; Stress Conc Compos Sci Technol, 59 (1999) 2125; Tech Textiles 43 (2000) 120; Compos Part A 31 (2000) 571; D 82 Dissertation RWTH Aaachen (1999)]. A detailed prediction of properties of the stitched reinforcements requires an understanding of the stitch formation process and the interaction between textile reinforcements, the stacking sequence thereof, the stitching process parameters and sewing thread properties.     

纺织机械企业计算机信息管理系统的设计

通过对纺织机械企业管理中有关信息的统计分析，利用SCO Open Server5.0网络操作系统、UNIX系统和ORA-CLE6数据库工具，开发出了以财务为中心、以生产为主线的管理模式的纺织机械制造业计算机信息管理系统。该系统能够实现网络数据信息的共享、调用、统计、打印等，为企业决策和发展提供适时的数据信息服务。     

A new lamination theory for layered textile composites that account for manufacturing induced effects

This paper is concerned with the development of a new lamination theory for layered textile composites that can account for manufacturing induced effects. The theory can be used for the calculation of the effective linear elastic extensional and bending stiffnesses of laminated textile composite panels. A representative unit cell (RUC) of the textile architecture is first identified along with its constituents. Tow geometry is represented analytically taking account of tow undulation. Each tow is modeled as a transversely isotropic linear elastic solid and the contribution from each tow to the RUC elastic bending stiffness is obtained by volume averaging, taking account of the volume fraction of each constituent. The formulation is amenable to the incorporation of geometric changes to the textile architecture that occurs through manufacturing induced consolidation. Predictions of the elastic bending stiffness are compared against experimental data, showing a strong correlation between the analytical model and the experimental results.     

基于天然纤维和热塑性树脂的包缠纺预型件:第2部分响应曲面方法模型的建立和过程优化

本文基于天然纤维和热塑性树脂,通过包缠纺纱工艺研究了包缠纱纺织预型件及其复合材料的加工性能.研究表明,中空锭捻度和中空锭转速是影响包缠纱预型件的纤维体积分数和性能的两个主要因素.并通过响应曲面方法建立了实验模型,来优化组合中空锭捻度和中空锭转速的参数以得到结构均匀的包缠纱线和预型件.结果表明该包缠纱适合于生产均一的预混料,可用于形成纺织结构预型件及复合材料.并且这些结果表明在许多不需要很高承载能力的应用中,用此方法加工的天然纤维复合材料有可能取代玻璃纤维复合材料.     

Comparing manufacturing and control practices in Europe and Korea

This paper presents a comparison of the manufacturing planning and control practices between firms in South Korea and Europe in the non-fashion textile and small machine tool industries. The key differences in practice were found in the details of forecasting and production planning, the market influence on shop-floor activities, the organizational level used in planning and control, and the level of sophistication in terms of computers and techniques used. The implications of these findings are important for firms with plans to enter into joint ventures or other cooperative arrangements. The data used in this study are from a large data base of actual manufacturing practices collected from countries around the world.     

An approach in modeling the temperature effect in thermo-stamping of woven composites

Made with high-strength continuous fibers, textile composites are of increasing interest in automotive and aerospace industries due to their high-strength/weight performance as compared to sheet metals. Nevertheless, significant reduction in manufacturing cost is required to use textile composites for mass production applications. Highly efficient thermo-stamping operations possess the potential to substantially reduce fabrication time and cost compared to the much slower autoclave forming process. In this paper, thermo-forming of woven fabric-reinforced thermo-plastic composites is simulated using a non-orthogonal material model. The temperature effect is taken into account by modifying the equivalent material properties for the composite sheet based on the contact status between the tooling and the blank. The approach is exemplified on the hemispherical thermo-stamping of a plain weave composite sheet.     

Multiple routeings and capacity considerations in group technology applications

This paper addresses the problem of manufacturing cell formation, given multiple part routeings, and multiple functionally similar workcentres. Cellular manufacturing is intended to facilitate production, and thus should be based on projected production requirements. The originality of the approach lies in considering both the manufacturing system as well as projected production, and distributing the demand among alternate routeings in order to obtain a better manufacturing cell design. The suggested choice of part routeings favours the decomposition of the manufacturing system into manufacturing cells in a way that minimizes part traffic, along with satisfying the part demand and workcentre capacity constraints. We show that the problem can be formulated as a linear programming type problem which simultaneously addresses two problems: (i) routeing selection, and (ii) cell formation. The common objective is to minimize the inter-cell traffic in the system. The proposed algorithm iteratively solves two problems. The first problem is formulated as a linear-programming problem, while the latter is approached by an existing heuristic bottom-up aggregation procedure, known as Inter-Cell Traffic Minimization Method (ICTMM), enhanced appropriately.     

Dislocation network in additive manufactured steel breaks strength–ductility trade-off

Most mechanisms used for strengthening crystalline materials, e.g. introducing crystalline interfaces, lead to the reduction of ductility. An additive manufacturing process – selective laser melting breaks this trade-off by introducing dislocation network, which produces a stainless steel with both significantly enhanced strength and ductility. Systematic electron microscopy characterization reveals that the pre-existing dislocation network, which maintains its configuration during the entire plastic deformation, is an ideal “modulator” that is able to slow down but not entirely block the dislocation motion. It also promotes the formation of a high density of nano-twins during plastic deformation. This finding paves the way for developing high performance metals by tailoring the microstructure through additive manufacturing processes.     

Measurement and Analysis of Drapeability Effects of Warp-Knit NCF with a Standardised,Automated Testing Device

Characterising the drapeability of reinforcement fabrics, is one of the most sought after abilities of those designing composite processes and components. This is not surprising as composite processes are being considered in a greater range of fields and applications. Drapeability effects are formed by the irregular rearrangement of fibres. This displacement can occur within the textile plane and result in fibre disorientations, undulations and gaps or the fibres can be pushed into the third dimension - forming wrinkles or loops. To measure such effects in non-crimp fabrics, the Textechno Drapetest automatic drapeability tester was developed. To show its viability as a tool for composite engineering, a set of fabrics was chosen to show that the influence of textile design parameters on drapeability effects is now quantifiable. The Textechno Drapetest uses a sophisticated digital image analysis system to measure the position and direction of fibres and conclude from this information on the extent and intensity of drapeability effects in the textile surface. To measure effects outside the surface, i.e. wrinkles, a laser triangulation sensor is employed. The textiles were varied in the production parameters of stitch point distance in machine direction (MD) and cross direction (CD), the weight per area, and the stitch pattern (tricot and chain). The measurements showed that the new test method is capable of measuring the effects that were expected from classical test setups as well as a range of additional effects. From the results a significant influence of the stitch yarn on the formation of effects can be deduced. Especially the density of stitch points is a parameter that lets the textile producer control the behaviour of the textile when they are formed into a doubly curved three dimensional shape. To control the gap formation, however, the spacing of the stitch points in machine or in crosswise direction is also of importance with a shorter stitch length decreasing the forming of gaps more than a tighter stitch yarn pitch.     

Agent-based distributed scheduling for virtual job shops

Nowadays, market globalisation and stiff world-wide competition require flexible, demand-driven, and reconfigurable production systems that can adapt to the requirements of the increasing reduction in product life cycle and rapid changes in market demand. The advent and development of network technology (especially the Internet) and distributed computing technology make it possible for geographically dispersed manufacturing resources to be integrated and deployed effectively and efficiently. In addition, manufacturing enterprises can expand their throughput within a short time and rapidly reduce the production cycle via transferring certain jobs to other available manufacturing resources in the globalised manufacturing environment, viz., manufacturing enterprises can expand their throughput through the dynamic formation of virtual job shops according to the production requirements. Owing to more open manufacturing environments and rapid changes of market demands, the traditional centralised scheduling approaches are not suitable for this open distributed manufacturing environment. This paper proposes a distributed scheduling approach in which a multi-agent solution towards a ‘task-machine’ assignment is presented. The main points of discussion are the formation of a virtual job shop that is based on market mechanism and the distributed scheduling approach based on negotiation.     

Textile composite double dome stamping simulation using a non-orthogonal constitutive model

Stamping is one of the most effective ways to form textile composites in industry for providing high-strength, low-weight and cost-effective products. This paper presents a fully continuum mechanics-based approach for stamping simulation of textile fiber reinforced composites by using finite element (FE) method. A previously developed non-orthogonal constitutive model is used to represent the anisotropic mechanical behavior of textile composites under large deformation during stamping. Simulation are performed on a balanced plain weave composite with 0°/90° and ±45° as initial yarn orientation over a benchmark double dome device. Simulation results show good agreement with experimental output in terms of a number of parameters selected for comparison. The effects of meshing and shear moduli obtained from bias extension test and picture frame test on forming simulation results are also investigated.